The Nets bought out and waived Rafer Alston yesterday and then quickly moved to add a third point guard by acquiring Chris Quinn plus a 2012 second-rounder from Miami, essentially giving up only a $1.2 million trade exception.

Alston, in the final year of his contract, agreed to a buyout of roughly $2.1 million of the $3.1 million he has left on the $5.25 million he makes in this, the final year of his contract.

Alston is expected to return to Miami once he clears waivers. He “very recently” made it clear he wanted to play elsewhere, interim coach/GM Kiki Vandeweghe said.

“It was more of an understanding,” Vandeweghe said of the move. “I was pleased we could help him out.”

Miami will pay the $640,000 remaining on Quinn’s $1.05 million salary. A fourth-season guard out of Notre Dame, he has been inactive all season.

The Nets receive a 2012 second-rounder while “trading” their 2010 second-rounder, which is protected to 50.